The Distributional Ecology of the Maned Sloth: Environmental Influences on Its Distribution and Gaps in Knowledge

Abstract

The maned sloth Bradypus torquatus (Pilosa, Bradypodidae) is endemic to a small area in the Atlantic Forest of coastal Brazil. It has been listed as a threatened species because of its restricted geographic range, habitat loss and fragmentation, and declining populations. The major objectives of this study were to estimate its potential geographic distribution, the climatic conditions across its distributional range, and to identify suitable areas and potential species strongholds. We developed a model of habitat suitability for the maned sloth using two methods, Maxent and Mahalanobis Distance, based on 42 occurrence points. We evaluated environmental variable importance and the predictive ability of the generated distribution models. Our results suggest that the species distribution could be strongly influenced by environmental factors, mainly temperature seasonality. The modeled distribution of the maned sloth included known areas of occurrence in the Atlantic Forest (Sergipe, Bahia, Espírito Santo, and Rio de Janeiro), but did not match the observed distributional gaps in northern Rio de Janeiro, northern Espírito Santo or southern Bahia. Rather, the model showed that these areas are climatically suitable for the maned sloth, and thus suggests that factors other than climate might be responsible for the absence of species. Suitable areas for maned sloth were located mainly in the mountainous region of central Rio de Janeiro throughout Espírito Santo and to the coastal region of southern Bahia. We indicate 17 stronghold areas and recommended survey areas for the maned sloth. In addition, we highlight specific areas for conservation, including the current network protected areas. Our results can be applied for novel surveys and discovery of unknown populations, and help the selection of priority areas for management and conservation planning, especially of rare and relatively cryptic species directed associated with forested habitats.

A Current Perspective on the Historical Geographic Distribution of the Endangered Muriquis (Brachyteles spp.): Implications for Conservation

“…[ 1 ] from the potential distribution even though the entire region had (and still has) suitable habitat ( Fig 2A ). This distribution gap has also been observed for the maned sloth ( Bradypus torquatus , Xenartha) [ 47 ]; for which, Moreira et al [ 47 ] associated this pattern based on the vegetation type, as well as on the historical process of vegetation changes and retraction that occurred along the Quaternary. The vegetation hypothesis may also explain a similar gap for B .…”

“…Initially we compiled bioclimatic information and altitude associated with each occurrence location separately by species. We avoided autocorrelation by excluding one variable from each pair of variables with very strong correlation (R 2 ≥ 0.8[ 45 ]) [ 46 , 47 ]. Preference was given to altitude and climate extremes (i.e., Max/Min Temperature of Warmest/Coldest Month rather than Mean Temperature of Warmest Quarter, cf.…”

High moon brightness and low ambient temperatures affect sloth predation by harpy eagles

“…Our results suggest important consequences for patterns of prey mortality through the tropical seasons of Neotropical forests. We, therefore, suggest that researchers, conservationists and practitioners can learn from natural fluctuations in predator–prey systems when designing management actions (such as reintroduction, release and translocation efforts) of both harpy eagles and their prey, since some of these prey species are also threatened ( Catzeflis et al, 2008 ; Moreira et al, 2014 ; Suscke et al, 2016 ). For instance, consequences of the harpy eagle reintroduction on the endemic maned sloth which is listed as Vulnerable in the Brazilian Atlantic Forest needs careful evaluation.…”

“…These features reinforce our premise that behavioural crypsis is the main antipredator strategy of sloths, which we suggest to be the underlying reasons for the patterns observed in our study. Indeed, the latitudinal boundaries of the geographic distribution of sloths are far more restricted than those of harpy eagles (Moreira et al, 2014;Miranda et al, 2019). Sloths of the Choloepus genus are distributed over tropical Central America and the pan-Amazonian region, while Bradypus also occur over the northern section of Atlantic Forest (Emmons & Feer, 1997).…”

“…As endothermic forest specialists, sloths (genus Bradypus and Choloepus, order Pilosa) exhibit relatively low basal metabolic rates and can only partially regulate body temperature (Pauli et al, 2016). Therefore, they need to bask and can be affected by even mild variation in habitat cover and thermally inappropriate microhabitats (Peery & Pauli, 2014;Giné et al, 2015), to the extent that temperature seasonality is highly influential on sloth behavioural ecology (Moreira et al, 2014).…”